Prior art nasal filters designed to be removably inserted into the nostrils offer various filter materials exhibiting a range of porosities.
Albu U.S. Pat. No. 3,463,149 discloses a filter plug comprising a cotton body contained within a fabric covering. A medicament containing cylinder, having a stationary ported piston received therein, dispenses medicament into the body upon relative movement of the cylinder and piston.
Kronenberg U.S. Pat. No. 10,322,304 B2 discloses a two-stage filter system including a microfiber filter and a nanofiber filter used in series, with the nanofiber filter located downstream of the microfiber filter.
Dolezal U.S. Pat. No. 7,918,224 B2 discloses a pair of ellipsoidal filters exhibiting a corrugated structure to increase the surface area available for filtration.
The entire contents of the foregoing Albu, Kronenberg, and Dolezal patents are hereby incorporated herein.
Presently known nasal filters are unsatisfactory in that they allow some portion of the inhaled air stream to bypass the seal formed between the outer perimeter of the filter and the internal nasal surfaces. In addition, very small particle sizes often pass through the filter and enter the body, potentially causing infection.
Nasal filter devices and systems are thus needed which overcome these and other shortcomings of the prior art.